AM: Sir Paul, first of all thank you very much for sparing us some time this afternoon to talk about Ecce Cor Meum. Is it right that you were asked to compose a piece by Magdalene College in Oxford and that was how it all came about? And you'd actually heard the college choir sing there?

PAUL: Yes, I was first of all asked by the then president Anthony Smith and he invited me to come and listen to the choir and look around. He wanted to inaugurate a new building and he wanted this piece for its opening but it took longer than I thought. Linda and I went up there. We stayed at the college, we went to the chapel and we heard the choir sing. It's a beautiful place and the choir were great, they were doing a lot of stuff I'd not heard before - I don't know what it was - but their choirmaster has interesting tastes. Some of it would be what you'd expect but some of it would be harmonically really interesting and I was thinking 'wow'.

AM: What did you start with first ­ was it the music or the subject matter of the commission?

PAUL: It was the music. I got so excited that I immediately started thinking of melodies and tunes and harmonies. I was doing it on a computer programme on a keyboard that had a choir so it sounded quite realistic. I thought that I could just play it into this keyboard and a score would appear. Of course that's not true, and anyone who knows anything about composing knows that. You have to set up a tempo and you have to stick strictly to that. If you want to alter from 4/4 let's say to 3/4 time, you've got to tell the computer that. And I didn't know all these things. Looking back on it now it's laughable, but it was quite a while ago, about 1997, when I started.

AM: What about the experience of having written the Liverpool Oratorio and Standing Stone? Did that help? Did you draw on your experiences of those two works for this?

PAUL: It's a funny thing for me. You make a great album, a successful album and you come to make your next one and you think; 'I know how to do it now because I just made a great one', but you don't. Each time you come to it you relearn the whole thing. It's as if you forget it all and your memory goes blank. In a way it's quite a good thing and what I used to do play the last album to remind me where we were up to and what I now wanted to try. So with the Oratorio and with Standing Stone, they obviously helped because they were experiences that I needed but it was still a blank canvas.

I'd been involved with another choir for a memorial for Linda, who'd died by this time and was obviously a huge setback to me. This is why I think the piece took so long to write. I started it and I had the whole thing going then suddenly Linda died and it just stopped me. And I had to take a year out just to grieve and then I picked it up after that. There's an interlude in the middle of Ecce Cor Meum, which is a very sad piece of music and I remember actually sitting at the keyboard, just weeping when we were doing this piece. It does it to me every time

AM:The words came about through a concert you were working with John Taverner - is that right? And inspiration struck thanks to a statue of Christ.

PAUL: I was at a reception connected with the memorial for Linda and there were choral writers there. And one of them asked me what I had used for the text and I didn't quite understand the question. It was only then I realised that most people do it the other way round from how I'd done it. They find a great French poem or a piece of Shakespeare and set it, which would have been really much easier. So then I started going about the process of the words and that was then the next stage.

I wasn't looking for something that was specifically Christian but John Taverner had asked me to narrate a piece of his that was by a Greek poet called Kadafi. I agreed to do it and went to New York to a church there - a very ornate, beautiful church. While I was waiting for my go, I was looking around the church and I saw a crucifixion statue up on the wall and I saw underneath it 'Ecce Cor Meum'. So dredged my mind for some Latin from school trying to work out what it meant. 'Ecce' meant 'behold', it was one of the key words ­ 'behold Caesar, ecce Caesar'. 'Cor' and 'Meum' meant 'heart' and 'mind'. So I realised it was 'behold my heart' and that started the idea for the lyrics.

AM:I wanted to ask you a bit about the performance because you recorded it at Abbey Road earlier in the year. Did you like being on hand to give feedback or do you just sit there quietly and speak when you're spoken to if anyone wants your opinion?

PAUL: A bit of both. I like being there ­ it's my baby. If there's a wrong note, I'll hear it. I know how it sounds so it's useful for them to have me there. Being a musician as well, I relate to the musicians and their task, so I don't give them a hard time. I try to be really sympathetic with them and I think that comes over. During the space of the week, we had quite a good time together. It's something that I don't do every day, even though I'm in a studio and work with orchestras, a whole big piece like that was quite an effort but when we finished it, it was very satisfying.

AM: Do you think you've started something of a trend? Other musicians have turned their hand to classical music like Elvis Costello; Sting is about to release an album of lute music and Chris Martin from Coldplay has said that when he's 40 he wants to go college to study classical music.

PAUL: I can sympathise with Chris Martin because when I'd written Eleanor Rigby in the 1960s I was excited by the idea that this wasn't a band it was actually just string players. For 'Yesterday', I had a string quartet and George Martin helped me. I'd go round to his house and I'd show him the chords and he would re-voice them for a quartet. In rock'n'roll I would play within one octave, but classical composers in the past would voice it. George would give me little tips on those sorts of things and we'd have fun moments. On 'Yesterday' George was taking chords down from me and looking at the voicing of them and there was one little bit where I wanted a seventh and George said 'a classical composer wouldn't do that' and I said 'all the more reason to do it, stick it in, come on.' We had nice little experimental moments like that. About the time of Eleanor Rigby I did have this image of myself in a kind of tweed jacket with patches on the elbows and a pencil and some manuscript paper and I thought that's what I'll do. That's what I'll do when The Beatles runs out.'

AM: Can I ask you just finally if there are any classical composers or pieces that you couldn't live without, you love to listen to or revisit from time to time.

PAUL: I do have lots of pieces I like but if I just had to choose something to go on a desert island, it would be Chopin's 'Nocturnes'. It's something I come back to all the time, so that would be my choice.